Sane behavior of fbset

["Antonino A. Daplas" <adaplas@hotpop.com>]

Hi,

Currently, using fbset either corrupts the display, or at worst, hangs the GPU.  I consider
this a critical bug.  I don't want to discuss the pros/cons of using fbset vs stty to
change the console size, but we need to make sure that using fbset (or any utility
that utilizes the fb_set_var ioctl) does not produce undefined behavior.  There are 
at least 3 possibilities:

1.  Revert to 2.4 behavior.  This is easy to add since fbdev already has a notifier 
support. (I already have working code for this). Of course, stty will still work.

2.  Make the set_var ioctl return immediately if the vc_mode of the current display is 
KD_TEXT. Basically, fbset becomes an informational utility only. I don't know the 
repercussions of this with userland fb applications though.

3.  Modify fbset (and other similar utilities, if there are any) so it also issues an 
'stty-like' call after a 'set_var' call.   

Note: As mentioned by many people before, it's almost impossible to completely 
preserve per-console mode info because of the lack of a per-display var.  So even 
if we agree to implement #1,  it cannot completely match 2.4 behavior. Also, the lack
of per-display var means that drivers must be able to handle mode changes without 
any help.  James' fb_find_mode support in fbcon_resize does partly alleviate this 
limitation.

Comments?

Tony




-------------------------------------------------------
This SF.Net email is sponsored by The 2004 JavaOne(SM) Conference
Learn from the experts at JavaOne(SM), Sun's Worldwide Java Developer
Conference, June 28 - July 1 at the Moscone Center in San Francisco, CA
REGISTER AND SAVE! http://java.sun.com/javaone/sf Priority Code NWMGYKND